A nitride semiconductor single crystal substrate, a manufacturing method thereof and a method for manufacturing a vertical nitride semiconductor device using the same. According to an aspect of the invention, in the nitride semiconductor single crystal substrate, upper and lower regions are divided along a thickness direction, the nitride single crystal substrate having a thickness of at least 100 μm. Here, the upper region has a doping concentration that is five times or greater than that of the lower region. Preferably, a top surface of the substrate in the upper region has Ga polarity. Also, according to a specific embodiment of the invention, the lower region is intentionally un-doped and the upper region is n-doped. Preferably, each of the upper and lower regions has a doping concentration substantially identical in a thickness direction.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A nitride single crystal substrate comprising: upper and lower regions having the same composition and divided along a thickness direction, the upper and lower regions having a thickness of at least 100 μm, wherein the upper region is grown on the lower region such that a top surface of the upper region has Ga Polarity, and the lower region has a thickness equal to or greater than that of the upper region, and wherein the lower region is un-doped and the upper region is n-doped such that the upper region has a doping concentration that is five times or greater than that of the lower region.
2. The nitride single crystal substrate according to claim 1 , wherein the lower region has a first doping concentration substantially uniform in a thickness direction of the lower region and the upper region has a second doping concentration substantially uniform in a thickness direction of the upper region.
3. The nitride single crystal substrate according to claim 1 , wherein the upper region has a doping concentration of at least 5×10 18 /cm 3 , and the lower region has a doping concentration up to 5×10 17 /cm 3 .
4. The nitride single crystal substrate according to claim 1 , wherein the substrate has a thickness ranging from 200 μl to 600 μm.
5. The nitride single crystal substrate according to claim 4 , wherein the lower region has a thickness ranging from 100 μm to 500 μm.
6. The nitride single crystal substrate according to claim 4 , wherein the upper region has a thickness ranging from 10 μm to 100 μm.
7. The nitride single crystal substrate according to claim 1 , wherein the nitride single crystal substrate comprises a material having a composition expressed by Al x In y Ga (1-x-y) N, where 0≦x≦1, 0≦y≦1, and 0≦x+y≦1.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
March 16, 2007
December 28, 2010
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